1. Field of the Invention
The invention relates to a vehicle suspension system; and more specifically to a suspension system having a twist beam axle and a method for controlling said suspension.
2. Description of Related Art
One example of a rear axle for motor vehicles having front-wheel drive is a twist beam axle. A twist beam axle generally includes two trailing arms, both of which are rigid with respect to torsion and bending, and which are attached to a pivotable crossbeam, i.e., torsion-flexible, but bending-rigid. The crossbeam typically has a U-shaped or T-shaped profile. In the event of deflection and rebound on both sides, the crossbeam behaves like a rigid axis. However, in the event of deflection and rebound on one side it twists and acts as a stabilizer. Wheel mounts, typically attached on the rear ends of the trailing arms, secure the vehicle wheels. The front ends of the trailing arms of the twist beam axle connect, via bearings, particularly rubber bearings, to the motor vehicle body. For a high level of travel comfort, the rubber bearings often comprise a soft material, wherein road irregularities are filtered out by the soft rubber bearings.
Variation of the travel direction of the motor vehicle results in lateral forces causing twisting and rocking of the twist beam axle, correspondingly resulting in changes of the wheel position in the longitudinal direction (toe change) and in the vertical direction (camber change) of the motor vehicle. These changes of the wheel position, by way of forces acting on the wheels in the transverse direction of the motor vehicle, can be calculated beforehand in consideration of the geometry of the wheels and the twist beam axle in particular and can be counteracted by design-based measures. In one case, for example using a harder material in the bearings achieves higher toe stability; however, the harder material, i.e., a hard bearing, provides less damping than a soft bearing.